It is known to provide high humidity refrigeration apparatus for maintaining a high humidity environment in a store in which vegetables such as lettuce, celery, cabbage, cauliflower can be kept immediately following harvesting. Such high humidity refrigeration apparatus is used so that field heat can be quickly removed from the harvested vegetables to inhibit dehydration.
In recent times it has been proposed to provide a shipping container with a high humidity refrigeration apparatus so that pallets, for example, containing the harvested vegetables, can be loaded into the shipping container in a field, and then subsequently removed in that shipping container to a distribution point.
The known high humidity refrigeration apparatus of this type comprises a heat exchanger which will provide high humidity to air that is fan forced through the goods. Typically, the heat exchanger comprises an open mesh structure on which cooled water collects. The open mesh structure provides a plurality of leading edges to the air, and as a consequence the air takes up moisture from the leading edges to increase the humidity of the air. The air, in turn, is passed into a chamber in which the vegetables are stored. Typically the water is first sprayed onto a cooling heat exchanger so that the water is cooled to a suitable temperature. The cooling heat exchanger is, in turn, cooled by conventional refrigeration apparatus. The humidity provided by such high humidity refrigeration apparatus is usually in the range 97 to 90% relative humidity. Typically the air flow required is in the range of 3000 ft.sup.3 to 36000 ft.sup.3 per minute.
In the known high humidity refrigeration apparatus, air which passes through the refrigeration apparatus is caused to enter the refrigeration apparatus either in a front wall thereof or at a lowermost region thereof. The air which is discharged is discharged from the top of the casing. Typically, the high humidity refrigeration apparatus is placed at one end of a chamber, and vegetables are loaded onto pallets which are successively stacked side by side in the chamber. A blind or curtain extends over the tops of the vegetables on the pallets to ensure that the discharged air from the high humidity refrigeration apparatus passes over the tops of all of the vegetables in the pallets and is then caused to flow successively through the side by side pallets from the end of the chamber remote from that where the high humidity refrigeration apparatus is located. In other words, the air passes and contacts the vegetables stacked on the pallets from the end of the side by side arranged pallets at an end of the chamber which can be opened to permit loading and/or unloading of the pallets.
We have realized there is a serious disadvantage in this prior art structure and method because the vegetables on the first loaded pallet are closest to the air inlet for the high humidity refrigeration apparatus. That, in turn, means that the air which passes through those vegetables is not the coldest or the highest humidity air which can be provided. Accordingly, the vegetables on the pallet which is first loaded may, in fact, be in an environment where there is insufficient cooling and humidity available to satisfactorily remove all of the field heat therefrom and as a consequence such vegetables may dehydrate.